The major objective of this project is to delineate the changes in the lens proteins which occur as a result of the cataractous process. Four specific areas of investigation will be pursued: 1. The delineation of the chemistry of high molecular weight protein and the relationship of its subunits to the low molecular weight soluble protein constituents; 2. The characterization of the chemistry of the water insoluble fraction and the relationship of its polypeptide constituents to other lens protein; 3. An investigation of the contribution to protein transformation and cataract formation of certain post-translational changes such as (a) oxidation; (b) increased charge heterogeneity and deamidation; (c) chain cleavage; (d) racemization; (e) formation of protein associated fluorescent groups; (f) crosslinking reaction involving interchain polypeptide linkage and protein-sugar bonds. 4. The mechanism by which lens polypeptides aggregate to normal sized and HMW and insoluble components.